Astronomical Society. 45*7 



for the purpose of trying the light, &c. of his telescopes, for which 

 the ring and satellites are good tests. The instruments which were 

 employed in the present investigations were two Newtonian reflec- 

 tors, — one, supposed by Watson, of 40 inches focus, and 6^ aper- 

 ture ; and another, by Dollond, of 68 inches focus, and 6f- aper- 

 ture. The first, under favourable circumstances, gives a most ex- 

 cellent image ; the latter is a very good instrument. The following 

 are extracts from the author's journal. 



" Nov. 25, 1825. — The double ring beautifully defined, perfectly 

 distinct all round, and the principal belts well seen. I tried many 

 concave lenses, and found that the image was much sharper than 

 with convex eye-glasses, and the light apparently much greater. 

 Dollond, 259 the best power; 480, a single lens, very distinct. 



" Nov. 30. — The night very favourable, but not equal to the 

 25th. The exterior ring of Saturn is not so bright as the interior, 

 and the interior is less bright close to the edge next the planet. 

 The inner edge appears more yellow than the rest of the ring, and 

 nearer in colour to the body of the planet. 



" Dec. 17. — The evening extremely fine. With Dollond I per- 

 ceived the outer ring of Saturn to be darker than the inner, and 

 the division of the ring all round, with perfect distinctness ; but 

 with Watson I fancied that I saw the outer ring separated by nu- 

 merous dark divisions extremely close, one stronger than the rest 

 dividing the ring about equally. This was seen with my most per- 

 fect single eye-glass power. A careful examination of some hours 

 confirmed this opinion. 



" Jan. 16 and 17, 1826. — Captain Kater believed that he saw the 

 divisions with the Dollond, but was not positive. Concave eye- 

 glasses found to be superior to convex. 



" Feb. 26, 1826. — The division of the outer ring not seen with 

 Dollond. 



"Jan. 22, 1828. — The evening remarkably fine, and the same 

 appearances shown as on the 30th November, 1825, but no divisions 

 seen in the outer ring. I am, therefore, the more persuaded that 

 they are not permanent." With the Dollond. 



On the 17th December, when the divisions were most distinctly 

 seen, Captain Kater made a drawing of the appearance of Saturn 

 and his rings. The phenomena were witnessed .by two other per- 

 sons on the same evening, one of whom saw several divisions in 

 the outer ring, while the other saw one middle division only ; but 

 '-he latter person was short-sighted, and unaccustomed to telescopic 

 observations. 



It will be remarked, that these divisions were not seen on other 

 evenings, which yet were considered very favourable for distinct 

 vision. 



It seems that the same appearances were seen by Mr. Short, but 

 the original record of his observations cannot be found. 



In Lalande's Astronomy (third edition), article 3351, it is said, 

 " Cassini remarked that the breadth of the ring was divided into 

 two equal parts by a dark line having the same curvature as the 



N. S. Vol. 8. No. 48. Dec. 1830. 3 N ring, 



